package com.itheima.reggie.controller;

import com.itheima.reggie.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.UUID;

/**
 * 文件上传下载
 */
@RestController
@RequestMapping("/common")
@Slf4j
public class CommonController {

    @Value("${reggie.path}")
    private String basePath;

    /**
     * 文件上传
     * @param file
     * @return
     */
    @PostMapping("/upload")
    public R<String> upload(MultipartFile file) {
        log.info(file.toString());
        //file是一个临时文件，程序执行结束后，会被删除，现在另存至别的位置
        String originalFilename =  file.getOriginalFilename();
        //后缀
        String suffix = originalFilename.substring(originalFilename.lastIndexOf("."));
        //使用UUID重新生成文件名，防止文件名称重复造成文件覆盖
        String fileName = UUID.randomUUID().toString() + suffix;

        File dir = new File(basePath);
        if(!dir.exists()){
            //目录不存在，创建
            dir.mkdirs();
        }

        //转存到指定位置
        try {
            file.transferTo(new File(basePath + fileName));
        } catch (IOException e) {
            e.printStackTrace();
//            throw new RuntimeException(e);
        }
        return R.success(fileName);
    }

    /**
     * 文件下载
     * @param name
     * @param response
     */
    @GetMapping("/download")
    public void download(String name, HttpServletResponse response) {

        try {
            //输入流，通过输入流读取文件内容
            FileInputStream fis = new FileInputStream(new File(basePath+name));

            //输出流，通过输出流将文件写回浏览器，在浏览器展示图片
            ServletOutputStream out = response.getOutputStream();

            //说明文件类型
            response.setContentType("image/jpeg");

            int len = 0;
            byte[] bytes = new byte[1024];
            while((len = fis.read(bytes))!=-1){
                out.write(bytes,0,len);
                out.flush();//刷新
            }

            //关闭资源
            out.close();
            fis.close();
        } catch (Exception e) {
            throw new RuntimeException(e);
        }
    }

}
